Associations between childhood trauma and adolescent psychiatric disorders in Brazil: a longitudinal, population-based birth cohort study.

Background: The mental health consequences of exposure to childhood trauma have been little studied among adolescents in low-income and-middle-income countries (LMICs), despite a relatively high burden of trauma in LMIC populations. We investigated associations between trauma and adolescent psychiatric disorders in the 2004 Pelotas Birth Cohort, Brazil.

Methods: In the 2004 Pelotas Birth Cohort, current psychiatric diagnoses (anxiety, mood, attention-hyperactivity, and conduct-oppositional disorders) were assessed at age 15 years (caregiver-report Development and Well-being Assessment), and age 18 years (self-report Mini-International Neuropsychiatric Interview). Lifetime cumulative trauma was assessed via caregiver report up to age 11 years and combined self-report and caregiver-report thereafter. Exposure to 12 trauma types were assessed (serious accident, fire, other disaster, attack or threat, physical abuse, sexual abuse, witnessed domestic violence, witnessed attack, witnessed accident, heard about attack, heard about accident, and parental death). Due to the high prevalence of trauma exposure in the sample, the number of different types of trauma exposure reported was extracted as a proxy for cumulative trauma load. We assessed both cross-sectional and longitudinal associations between cumulative trauma load and psychiatric disorders during adolescence using logistic regression, adjusting for confounders and pre-existing child psychopathology at 48 months. We also computed population attributable fractions (PAFs) for trauma-mental health associations at age 18 years.

Findings: 4229 adolescents (51·9% male, 48·1% female) were included in logistic regression analyses based on imputed data. Trauma exposure affected 81·2% of adolescents by age 18 years. At age 15 years, the odds of any disorder (adjusted odds ratio [aOR] 1·19 [95% CI 1·03-1·38]), anxiety disorders (1·45 [1·21-1·75]), and conduct-oppositional disorders (1·60 [1·13-2·27]) increased for each category increase in cumulative trauma, but mood and attention-hyperactivity disorders were not related to cumulative trauma. At age 18 years, the odds of any disorder (1·34 [1·24-1·44]), anxiety disorders (1·23 [1·13-1·34]), mood disorders (1·33 [1·22-1·46]), attention-hyperactivity disorders (1·24 [1·09-1·41]), and conduct-oppositional disorders (1·59 [1·36-1·86]) all increased for each category increase in cumulative trauma. In longitudinal analyses, each category increase in cumulative trauma by age 11 years was associated with an increased odds of any disorder (aOR 1·26 [95% CI 1·11-1·44]), anxiety disorders (1·27 [1·04-1·56]), and conduct-oppositional disorders (1·43 [1·04-1·97]) at 15 years; and trauma up to age 15 years was associated with increased odds of any disorder (1·32 [1·21-1·45]), anxiety disorders (1·27 [1·14-1·40]), mood disorders (1·26 [1·12-1·41]), and conduct-oppositional disorders (1·52 [1·24-1·87]) at age 18 years. Trauma up to age 11 years was not predictive of disorders at age 18 years, and there were no longitudinal associations between trauma and attention-hyperactivity disorders. PAF estimates indicated that trauma exposure accounted for 30·6% (95% CI 21·2-38·7) of psychiatric disorders at age 18 years.

Interpretation: Increasing exposure to trauma is associated with mental disorders among Brazilian adolescents. Given the high prevalence of trauma in LMIC populations, strategies to reduce exposure, identify those at greatest risk of mental disorders following trauma, and mitigate the consequences are crucial.

Funding: Wellcome Trust, WHO, National Support Program for Centers of Excellence, Brazilian National Research Council, Brazilian Ministry of Health, Children's Pastorate, São Paulo Research Foundation, Rio Grande do Sul Research Foundation, L'Oréal-Unesco-ABC Program for Women in Science in Brazil-2020, All for Health Institute, University of Bath, Economic and Social Sciences Research Council.

Translation: For the Portuguese translation of the abstract see Supplementary Materials section.